There are a number of door cladding or metallic door casing inventions. In Noach, U.S. Pat. No. 4,793,109; a profiled steel door jamb is attached over a facing wooden door frame using screws which can only be inserted the desired distance for correct positioning. In Kuffner, U.S. Pat. No. 4,179,849; a door frame assembly is made of first and second aluminum extrusions which can be placed in a door opening after the wall is finished. The assembly is attached to steel anchor plates fastened to the wall in the door frame opening. In Williams, U.S. Pat. No. 4,126,975; a metal door jamb of two piece overlapped constructions are secured together by a screw and clamp portion. In Kirton, U.S. Pat. No. 3,881,279; elongated members transversely slideably adjustable provide a variable width to a door frame. In Lehman, U.S. Pat. No. 3,654,734; pre-assembled U-shaped members, which include assembly plates, are secured together by fastening elements. In Pond, U.S. Pat. No. 3,520,085; an adjustable door frame uses side jamb and head jamb combinations consisting of two overlapping and contiguous members for walls of various thickness. In Cline, U.S. Pat. No. 3,420,003; an adjustable door frame for varying wall thickness uses a plurality of backing plates along an edge of the wall opening having a series of ratchet teeth to engage a gripping edge on the trim strips. In Mascari, U.S. Pat. No. 2,860,744; an adjustable door frame uses overlapping parts and ratchet engagement means. In Philip, U.S. Pat. No. 2,454,523; a door frame casement uses telescopic engagement to another part to accommodate different widths. In Thye, U.S. Pat. No. 1,715,579; a pair of cooperating members mounted on opposite sides of a wall overlap to provide coverage.
All of these approaches utilize a variety of structures and fastening means to cover a door frame whereas the instant invention uses only the generally planar cladding itself to provide similar results.